350 SHELLS AND SHELL-FISH. PART II. 



Pyramidea Sw. Imperforate ; spire much elevated_, 

 pyramidical, acute ; basal whorl beneath much flat- 

 tened, and scarcely convex ; pillar spiral, the base 

 very short, turning inwards, and then outwards, but 

 smooth ; outer lip thin; inner wanting.* (^fig. IO9. c.) 

 obalisca. Mart, 160. f. Nilotica. Mart. 168. f. 1614. 



1511, 1512. virgata. lb. 160. f. 1514. 



foveolata Gm. Mart. 161. f. marmorata. lb. 167. f. 1606. 



1516, 1517. Mauritiana. lb. 163. f. 1547. 



Lamprostoma Sw. Umbilicated ; pyramidical, spire 

 elevated, acute ; basal whorl much flattened beneath, 

 slightly convex ; pillar spiral ; the base short, and 

 marked by distinct plaits ; aperture striated ; inner 

 lip wanting. 



L. maculata. Mart. 168. f. 1515, 1516. 



Carinidea Sw. Imperforate ; spire pyramidical, acute ; 

 basal whorl concave beneath, and carinated round its 

 circumference ; aperture oval, entire, slightly angu- 

 lated at the base of the pillar, which turns inwards. 

 C. concavus. Mart. 168. f. brevispinus. ? Sow. Gen. 

 1620, 1621. (Turho.) f. 1. 



Tbochus Linn. Operculum horny ; shell trochiform ; 

 the basal whorl broad ; aperture oval ; sometimes an- 

 gulated by the union of the pillar and the outer lip, 

 but rarely toothed or striated, f 



Chlorostoma Sw. Deeply umbilicated almost to the 

 top of the spire ; inner lip forming a semi-margin to 

 the umbilicus ; outer lip angulated at the base, with 

 one or two tubercles ; body-whorl almost flat be- 

 neath, and nearly carinated at its edge ; aperture 

 remarkably oblique : representing Monilea.^ 

 C. argyrostoma. Mart. 165. f. 1362, 1363. 

 umbOicaris. lb. 171. f. 1666. 



* Troch. Niloticus is probably osculent between this and Lamprostoma j 

 but I have not seen a thoroughly full-grown specimen, with the mouth 

 quite formed : the operculum is said to be horny ; but this may be 

 doubted. 



t Except in Trockidon, which represents Monodonta Lam. in this circle. 



X Troch. merula Lam. connects this sub-genus with Pagodella. 



